German Patent Application No. 39 43 005 describes an electromagnetically actuatable fuel injection.
From German Patent 39 43 005 an electromagnetically actuatable fuel injection valve, in which a plurality of disk-shaped elements is arranged in the area of the seat. When the magnetic circuit is excited, a planar valve plate acting as a planar armature is lifted off a valve seat plate, situated opposite and cooperating with it, which together form a plate valve part. Upstream of the valve seat plate, a swirl element is arranged that sets the fuel flowing to the valve seat in a circular swirling motion. A stop plate sets a limit to the axial path of the valve plate on the side opposite the valve seat plate. The valve plate is surrounded by the swirl element such that it has a lot of play; the swirl element thus takes on a certain guiding function of the valve plate. In the swirl element a plurality of tangentially running grooves is introduced on its lower end face, the grooves extending from the external periphery to a central swirl chamber. If the swirl element is placed with its lower end face on the valve seat plate, the grooves function as swirl channels.
International Publication No. WO 96/11335 describes a fuel injection valve at whose downstream end a multi-disk atomizing attachment having a swirl-generating device is arranged. This atomizing attachment is provided on a valve seat support (member) downstream of a disk-shaped guide element installed in the valve seat support and of a valve seat also on the valve seat support, the atomizing attachment being held in a defined position by an additional supporting element. The atomizing attachment is executed so as to have two or four disks, the individual disks being made of stainless-steel or silicon. Correspondingly, in manufacturing the orifice geometries in the disks, conventional processing methods are used such as eroding, stamping, or etching. Each individual disk of the atomizing attachment is manufactured separately, in accordance with which, depending on the desired number of disks, all disks of the same size are stacked up one on the other to produce the complete atomizing attachment.
German Patent Application No. 196 07 288 describes so-called multilayer electroplating in detail for the manufacture of perforated disks that are suitable for use in fuel injection valves. This manufacturing principle of disk production, as described in German Patent Application No. 196 07 288 involving the multiple electroplating metal deposition of various structures on top of each other so that one-piece disk results, is expressly incorporated herein by reference. Micro-electroplating metal deposition in a plurality of planes, levels, or layers is also used in the manufacture of swirl disks according to the invention.
A swirl disk of the present invention has the characterizing features of claim 1 has the advantage that it can be manufactured in a particularly simple manner so as to be cost-effective. A particular advantage lies in the fact that the swirl disks can be manufactured extremely precisely in very large batches at one time (high batch capacity). Due to their metal construction, swirl disks of this type are very break resistant and easy to install, for example in injection valves or other spray-discharge nozzles for liquids of all types. The use of multilayer electroplating permits extremely great freedom of design, since the contours of the orifice areas (intake areas, swirl channels, swirl chamber, outlet orifice) in the swirl disk can be freely selected. Particularly in comparison with silicon disks, in which the achievable contours are rigidly prescribed on the basis of the crystal axes (pyramid stubs), this design flexibility is very advantageous.
In comparison to the production of silicon disks, metal deposition has the advantage of a very large variety of materials. The most various metals having their varying magnetic properties and hardnesses can be used in the micro-electroplating process employed in manufacturing the swirl disks. The varying hardnesses of the various metals can be used in a particularly advantageous manner, in that a material area is created having sealing properties.
The great technical freedom of design of the contours within the swirl disk in turn results in the great advantage that various stream shapes of the spray to be discharged can be generated in a simple manner. Thus it is possible to obtain stream profiles and sprays in the form of hollow cones, slanted hollow cones, solid cones, slanted solid cones, cones having skeins, or planar streams, which are all advantageously generated by the swirl-generating effects in the swirl disk. Using multilayer electroplating, it is possible to obtain extremely high-precision undercuts and overlaps in a particularly advantageous manner, cost effectively and without difficulty.
It is particularly advantageous to construct the swirl disk having three layers by carrying out three electroplating steps for the metal deposition. In this context, the upstream layer represents a cover layer, which completely covers the swirl chamber of a central swirl-producing layer. The swirl-producing layer is formed by one or more material areas, which due to their contouring and their geometrical position with respect to each other indicate the contours of the swirl chamber and of the swirl channels. As a result of the electroplating process, the individual layers are designed without separating or joining points so that they represent an uninterruptedly homogeneous material. To this extent, xe2x80x9clayersxe2x80x9d should be understood as a conceptual aid.
In an advantageous manner, provision is made in the swirl disk for two, three, four, or six swirl channels. The material areas, in accordance with the desired conturing of the swirl channels, can have very different shapes, e.g., bar-shaped or spiral-shaped. In an advantageous manner, the contours of the swirl chamber, the cover layer, and the outlet orifice can be designed in a flexible manner, it being possible through the asymmetries of certain orifice contours to generate particularly suitable, e.g., engine-specific stream images and spray shapes. The production of sprays or streams inclined with respect to the axis of symmetry of the swirl disk at an angle xcex3 (hollow or solid cones, a large or small skein component over the periphery, equal or unequal distribution over the periphery, non-rotationally symmetrical (planar-) stream shapes having adjustable skein components) in a simple manner and without additional components having prescribed diagonal spray-discharge contours (diagonal holes) represents an extraordinarily important advantage of the swirl disks of the present invention.
In a particularly advantageous manner, the swirl disk is executed such that the material areas are shaped so as to diverge from each other such that all the swirl channels have a different orientation with respect to the symmetrical axis of the swirl disk. Seen from around the periphery of the swirl disk, the swirl channels run such that their radial orientations and their tangential swirl orientations are continually changing in the reverse direction (when viewed from one swirl channel to another swirl channel). In a simple manner, a shaping of this type makes it possible to spray-discharge a swirl-impacted rotationally-symmetrical hollow-cone spray having equal distribution across the hollow-cone periphery. Sprays that are tilted with respect to the axis of symmetry and have the above-mentioned properties can be produced without downstream precision-manufactured components.
The fuel injection valve of the present invention has the advantage that it makes it possible to achieve a very high atomization quality of a fuel to be spray-discharged, as well as a stream or spray shape, that reflects the given requirements (e.g., installation conditions, engine configurations, cylinder shapes, spark plug positions). As a consequence, through the use of multilayer-electroplated swirl disks in an injection valve of an internal combustion engine, inter alia, the exhaust gas emissions of the internal combustion engine can be reduced, and similarly fuel consumption can be reduced.
From the advantages indicated above with regard to the swirl disks, corresponding advantages for the use in a fuel injection valve can also be deduced, because, as a result of the simplified and easy-to-reproduce mode of production of the swirl disks, coupled with the high functionality of the swirl generation in the liquid, there are for the fuel injection valve precisely the same advantages of high quality, equal and fine atomization, high variability in stream shapes, and cost effectiveness.
In operating an engine, the problem generally arises in the direct injection of gasoline that the downstream tip of the injection valve extending into the combustion chamber is coked by gasoline deposits. In the conventional injection valves extending into the combustion chamber, the danger therefore exists, through their service life, of a negative influence on the spray parameters (e.g., static flow quantities, stream angles), that can lead to a failure of the injection valve. By using a multilayer-electroplated swirl disk made of the materials nickel or nickel-cobalt and situated at the downstream end of the fuel injection valve, the coking in this area is effectively prevented. Other suitable materials are cobalt- and nickel-oxide and oxides of alloys of the aforementioned metals. By constructing the swirl disk out of materials of this type, a complete combustion of soot particles is catalyzed, and the deposition of carbon particles is prevented. Catalytic effectiveness is also shown by the rare metals, Ru, Rh, Pd, Os, Ir, and Pt, and by alloys of these metals, with each other or with other metals.
Further advantages are listed in greater detail in the following description of the exemplary embodiments.